The mission of this Shared Resource is to provide histologic and hematopoietic research support services to UCSF Comprehensive Cancer Center (CCC) investigators studying the pathogenesis and treatment of organ and hematologic malignancies in mouse models of human cancer. This facility provides services for members of many of the CCC programs. Histology services include processing, embedding, and histologic sectioning of murine tissues in paraffin and frozen blocks (with re-embedding of tissue as necessary), routine histochemical staining (hematoxylin and eosin) and other special histochemical stains. The Shared Resource also provides expertise in murine hematology. Complete blood counts are provided for investigators, including preparation of blood smears for analysis of white blood cell, red blood cell, and platelet morphology. In addition, the Shared Resource assists investigators analyzing hematopoietic tissues, including cytologic and histologic preparations of bone marrow, spleen, and lymph nodes. Another service provided by the Shared Resource is access to outside veterinary laboratory testing (e.g. serum chemistry assays). The Shared Resource runs a mouse pathology workshop, provides pathologic consultation, and provides both training on and access to the equipment utilized for pathologic analyses of mice. The Mouse Pathology Shared Resource was used by laboratory personnel representing 50 different investigators at the CCC, providing a total of 14,051 units of service during the most recent 12 month period. Investigators in many of the CC programs have relied upon the Shared Resource not only for direct services, but also for the training of their personnel. The results of the Mouse Pathology Shared Resource are evident in the extensive publications that reflect the use of mouse models by the investigators that utilize this service.